Polymer composition for the manufacture of injection moulded articles

ABSTRACT

This invention relates to a polymer composition that is particularly suitable for use in the manufacture of injection moulded articles, which can be biodegraded in industrial composting. This invention also relates to a process for the production of the said composition and articles obtained thereby.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Phase filing under 35 U.S.C. § 371 of PCT/EP2016/068233 filed on Jul. 29, 2016; and this application claims priority to Application No. 102015000040869 filed in Italy on Jul. 31, 2015 under 35 U.S.C. § 119. The entire contents of each application are hereby incorporated by reference.

This invention relates to a polymer composition that is particularly suitable for use in the manufacture of articles moulded by means of injection moulding, which can be biodegraded in industrial composting.

This invention also relates to a process for the production of the said composition and articles obtained thereby.

As is known, the techniques of hot moulding plastics materials, such as injection moulding, mainly find application in the production of articles having a high resistance to deformation, such as for example disposable cutlery, containers, tubs, plates or capsules for the dispensing of beverages, with walls having thicknesses typically greater than 200 microns.

Although the manufacture of articles with such great thicknesses ensures the necessary properties of resistance to deformation, it nevertheless creates difficulties in ensuring that these articles, when are made with polymers which are themselves biodegradable, have disintegratability properties rendering them suitable in plants for industrial composting.

In view of the above it would be desiderable to have a composition capable of being transformed economically and productively into moulded articles, without adversely affecting compostability.

It has now surprisingly been discovered that it is possible to meet this requirement by means of a polymer composition for the production of injection moulded articles comprising:

-   i) 20-60% by weight, preferably 30-50% by weight, with respect to     the sum of components i.-v. of at least one polyester comprising:     -   a) a dicarboxylic component comprising, with respect to total         dicarboxylic component:         -   a1) 0-20% in moles, preferably 0-10% in moles, of units             deriving from at least one aromatic dicarboxylic acid,         -   a2) 80-100% in moles, preferably 90-100% in moles, of units             deriving from at least one saturated aliphatic dicarboxylic             acid,         -   a3) 0-5% in moles, preferably 0.1-1% in moles, more             preferably 0.2-0.7% in moles, of units deriving from at             least one unsaturated aliphatic dicarboxylic acid;     -   b) a diol component comprising, with respect to total diol         component:         -   b1) 95-100% in moles, preferably 97-100% in moles, of units             deriving from at least one saturated aliphatic diol;         -   b2) 0-5% in moles, preferably 0-3% in moles, of units             deriving from at least one unsaturated aliphatic diol; -   ii) 30-60% by weight, preferably 35-50% by weight, with respect to     the sum of components i.-v., of at least one polyhydroxyalkanoate; -   iii) 0.01-5% by weight, preferably 0.02-3% by weight, with respect     to the sum of components i.-v., of at least one cross-linking agent     and/or a chain extender comprising at least one compound having di-     and/or multiple functional groups comprising isocyanate, peroxide,     carbodiimide, isocyanurate, oxazoline, epoxy, anhydride or divinyl     ether groups and mixtures thereof; -   iv) 0-10% by weight, preferably 0.1-9% by weight, with respect to     the sum of components i.-v., of at least one filler agent; -   v) 2-30% by weight, preferably 5-25% by weight, with respect to the     sum of components i.-v., of plant fibres.

With regard to the polyesters of the composition according to this invention, these comprise a dicarboxylic component which comprises, with respect to total dicarboxylic component, 0-20% in moles, preferably 0-10% in moles of units deriving from at least one aromatic dicarboxylic acid and 80-100% in moles, preferably 90-100% in moles of units deriving from at least one saturated aliphatic dicarboxylic acid and 0-5% in moles, preferably 0.1-1% in moles, more preferably 0.2-0.7% in moles, of units deriving from at least one unsaturated aliphatic dicarboxylic acid.

The aromatic dicarboxylic acids are preferably selected from aromatic dicarboxylic acids of the phthalic acid type, preferably terephthalic acid or isophthalic acid, more preferably terephthalic acid, and heterocyclic dicarboxylic acids, preferably 2,5-furandicarboxylic acid, 2,4-furandicarboxylic acid, 2,3-furandicarboxylic acid, 3,4-furandicarboxylic acid, more preferably 2,5-furandicarboxylic acid, their esters, their salts and their mixtures. In a preferred embodiment the said aromatic dicarboxylic acids comprise:

-   -   from 1 to 99% in moles, preferably from 5 to 95% and more         preferably from 10 to 80%, of terephthalic acid, its esters or         its salts;     -   from 99 to 1% in moles, preferably from 95 to 5% and more         preferably from 90 to 20%, of 2,5-furandicarboxylic acid, its         esters or its salts.

The saturated aliphatic dicarboxylic acids are preferably selected from C₂-C₂₄, preferably C₄-C₁₃, more preferably C₄-C₁₁, saturated dicarboxylic acids their C₁-C₂₄, preferably C₁-C₄, alkyl esters, their salts and their mixtures.

Preferably the saturated aliphatic dicarboxylic acids are selected from: succinic acid, 2-ethylsuccinic acid, glutaric acid, 2-methylglutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid, brassylic acid and their C₁₋₂₄ alkyl esters.

In a preferred embodiment of this invention the saturated aliphatic dicarboxylic acids comprise mixtures comprising at least 50% in moles, preferably more than 60% in moles, more preferably more than 65% in moles of succinic acid, adipic acid, azelaic acid, sebacic acid, brassylic acid, their C₁-C₂₄, preferably C₁-C₄, esters and their mixtures.

The unsaturated aliphatic dicarboxylic acids are preferably selected from itaconic acid, fumaric acid, 4-methylene-pimelic acid, 3,4-bis (methylene) nonandioic acid, 5-methylene-nonandioic acid, their C₁-C₂₄, preferably C₁-C₄, alkyl esters, their salts and their mixtures.

In a preferred embodiment of this invention the unsaturated aliphatic dicarboxylic acids comprise mixtures comprising at least 50% in moles, preferably more than 60% in moles, more preferably more than 65% in moles of itaconic acid, its C₁-C₂₄, preferably C₁-C₄ esters. More preferably, the unsaturated aliphatic dicarboxylic acids comprise itaconic acid.

The diol component of the polyesters of the composition according to this invention comprises 95-100% in moles, preferably 97-100% in moles, of units deriving from at least one saturated aliphatic diol, with respect to total diol component, and 0-5% in moles, preferably 0-3% in moles, with respect to total diol component, of units deriving from at least one unsaturated aliphatic diol. In a preferred embodiment, the diol component of the polyesters of the composition according to this invention consists of saturated aliphatic diols. With regard to the saturated aliphatic diols, these are preferably selected from 1,2-ethandiol, 1,2-propandiol, 1,3-propandiol, 1,4-butandiol, 1,5-pentandiol, 1,6-hexandiol, 1,7-heptandiol, 1,8-octandiol, 1,9-nonandiol, 1,10-decandiol, 1,11-undecandiol, 1,12-dodecandiol, 1,13-tridecandiol, 1,4-cyclohexandimethanel, neopentylglycol, 2-methyl-1,3-propandiol, dianhydrosorbitol, dianhydromannitol, dianhydroiditol, cyclohexandiol, cyclohexanmethandiol, dialkyleneglycols and polyalkylene glycols with a molecular weight of 100-4000, such as for example polyethylene glycol, polypropylene glycol and their mixtures. Preferably the diol component comprises at least 50% in moles of one or more diols selected from 1,2-ethandiol, 1,3-propandiol, 1,4-butandiol. More preferably the diol component comprises, or consists of, 1,4-butandiol.

With regard to the unsaturated aliphatic diols these are preferably selected from cis 2-buten-1,4-diol, trans 2-buten-1,4-diol, 2-butyn-1,4-diol, cis 2-penten-1,5-diol, trans 2-penten-1,5-diol, 2-pentyn-1,5-diol, cis 2-hexen-1,6-diol, trans 2-hexen-1,6-diol, 2-hexyn-1,6-diol, cis 3-hexen-1,6-diol, trans 3-hexen-1,6-diol, 3-hexyn-1,6-diol.

With regard to polyesters i. in the composition, these are preferably selected from aliphatic polyesters (“AP”) and aliphatic-aromatic polyesters (“AAPE”).

In the meaning of this invention, by aliphatic polyesters AP are meant polyesters comprising a dicarboxylic component which consists, with respect to the total moles of the dicarboxylic component, 95-100% in moles of at least one saturated aliphatic dicarboxylic acid and 0-5% in moles of at least one unsaturated aliphatic dicarboxylic acid and a diol component comprising, with respect to the total moles of the diol component, 95-100% in moles of units deriving from at least one saturated aliphatic diol and 0-5% in moles of units deriving from at least one unsaturated aliphatic diol.

By AAPE polyesters, in this invention are meant polyesters comprising a dicarboxylic component which consists at least one aromatic dicarboxylic acid compound, at least one saturated aliphatic dicarboxylic acid and 0-5% in moles, with respect to the total moles of the dicarboxylic component, of at least one unsaturated aliphatic dicarboxylic acid, and a diol component comprising, with respect to the total moles of the diol component, 95-100% in moles of units deriving from at least one saturated aliphatic diol and 0-5% in moles of units deriving from at least one unsaturated aliphatic diol.

In the case of the AP aliphatic polyesters, those preferred are polyesters in which the dicarboxylic component comprises units deriving from at least one C₂-C₂₄, preferably C₄-C₁₃, more preferably C₄-C₁₁ saturated aliphatic dicarboxylic acid, their C₁-C₂₄, preferably C₁-C₄ alkyl esters, their salts and their mixtures, and a diol component comprising units deriving from at least one saturated aliphatic diol, preferably selected from 1,2-ethandiol, 1,2-propandiol, 1,3-propandiol, 1,4-butandiol.

In a preferred embodiment of this invention, polyester i. of the composition comprises at least one aliphatic polyester (AP), preferably poly(1,4-butylene succinate), poly(1,4-butylene adipate), poly(1,4-butylene azelate), poly(1,4-butylene sebacate), poly(1,4-butylene adipate-co-1,4-butylene succinate), poly(1,4-butylene azelate-co-1,4-butylene succinate), poly(1,4-butylene sebacate-co-1,4-butylene succinate), poly(1,4-butylene succinate-co-1,4-butylene adipate-co-1,4-butylene azelate). In a particularly preferred embodiment the said aliphatic polyester is poly(1,4-butylene succinate).

In a further preferred embodiment of this invention the polyester of the composition comprises at least one aliphatic-aromatic polyester (AAPE), and is advantageously selected from:

-   -   (A) polyesters comprising repetitive units deriving from         aromatic dicarboxylic acids of the phthalic acid type,         preferably terephthalic acid, aliphatic dicarboxylic acids and         aliphatic diols (AAPE-A), characterised by an aromatic units         content of between 35 and 60% in moles, preferably between 40         and 55% in moles with respect to the total moles of the         dicarboxylic component. The AAPE-A polyesters are preferably         selected from: poly(1,4-butylene adipate-co-1,4-butylene         terephthalate), poly(1,4-butylene sebacate-co-1,4-butylene         terephthalate), poly(1,4-butylene azelate-co-1,4-butylene         terephthalate), poly(1,4-butylene brassylate-co-1,4-butylene         terephthalate), poly(1,4-butylene succinate-co-1,4-butylene         terephthalate), poly(1,4-butylene adipate-co-1,4-butylene         sebacate-co-1,4-butylene terephthalate), poly(1,4-butylene         azelate-co-1,4-butylene sebacate-co-1,4-butylene terephthalate),         poly(1,4-butylene adipate-co-1,4-butylene         azelate-co-1,4-butylene terephthalate), poly(1,4-butylene         succinate-co-1,4-butylene sebacate-co-1,4-butylene         terephthalate), poly(1,4-butylene adipate-co-1,4-butylene         succinate-co-1,4-butylene terephthalate). poly(1,4-butylene         azelate-co-1,4-butylene succinate-co-1,4-butylene         terephthalate).     -   (B) polyesters comprising repetitive units deriving from         heterocyclic dicarboxylic acids, preferably         2,5-furandicarboxylic acid, aliphatic dicarboxylic acids and         aliphatic diols (AAPE-B), characterised by an aromatic units         content of between 50 and 80% in moles, preferably of between 60         and 75% in moles with respect to the total moles of the         dicarboxylic component. The AAPE-B polyesters are preferably         selected from: poly(1,4-butylene adipate-co-1,4-butylene         2,5-furandicarboxylate), poly(1,4-butylene         sebacate-co-1,4-butylene 2,5-furandicarboxylate),         poly(1,4-butylene azelate-co-1,4-butylene         2,5-furandicarboxylate), poly(1,4-butylene         brassylate-co-1,4-butylene 2,5-furandicarboxylate),         poly(1,4-butylene succinate-co-1,4-butylene         2,5-furandicarboxylate), poly(1,4-butylene         adipate-co-1,4-butylene sebacate-co-1,4-butylene         2,5-furandicarboxylate), poly(1,4-butylene         azelate-co-1,4-butylene sebacate-co-1,4-butylene         2,5-furandicarboxylate), poly(1,4-butylene         adipate-co-1,4-butylene azelate-co-1,4-butylene         2,5-furandicarboxylate), poly(1,4-butylene         succinate-co-1,4-butylene sebacate-co-1,4-butylene         2,5-furandicarboxylate), poly(1,4-butylene         adipate-co-1,4-butylene succinate-co-1,4-butylene         2,5-furandicarboxylate), poly(1,4-butylene         azelate-co-1,4-butylene succinate-co-1,4-butylene         2,5-furandicarboxylate).

In addition to the dicarboxylic component and the diol component, the polyesters of the composition according to this invention preferably comprise repetitive units deriving from at least one hydroxy acid in a quantity of between 0 and 49%, preferably between 0 and 30% in moles with respect to the total moles of the dicarboxylic component. Examples of convenient hydroxyacids are glycolic, hydroxybutyric, hydroxycaproic, hydroxyvaleric, 7-hydroxyheptanoic, 8-hydroxycaproic, 9-hydroxynonanoic and lactic acids or lactides. The hydroxyacids may be inserted in the chain as such or may also be first caused to react with diacids or diols.

Long molecules with two functional groups including functional groups which are not in a terminal position may also be present in quantities of not more than 10% in moles with respect to the total moles of the dicarboxylic component. Examples are dimer acids, ricinoleic acid and acids incorporating epoxy functional groups and also polyoxyethylenes with molecular weights of between 200 and 10000.

Diamines, aminoacids and aminoalcohols may also be present in percentages up to 30% in moles with respect to the total moles of the dicarboxylic component.

During preparation of the polyesters of the composition according to this invention one or more molecules with multiple functional groups in quantities of between 0.1 and 3% in moles with respect to the total moles of the dicarboxylic component (as well as any hydroxyacids) may also advantageously be added in order to obtain branched products. Examples of these molecules are glycerol, pentaerythritol, trimethylolpropane, citric acid, dipentaerythritol, acid triglycerides, polyglycerols.

The molecular weight Mn of the polyesters of the composition according to this invention is preferably ≥20000, more preferably ≥40000. As far as the polydispersity index of the molecular weights Mw/Mn is concerned, this is instead preferably between 1.5 and 10, more preferably between 1.6 and 5 and even more preferably between 1.8 and 2.7.

The molecular weights M_(n) and M_(w) may be measured by means of Gel Permeation Chromatography (GPC). The determination may be performed with the chromatography system maintained at 40° C., using a set of three columns in series (particle diameter 5 μm and porosities of 500 Å, 10000 Å and 100000 Å) respectively, a refractive index detector, chloroform as eluent (flow 1 ml/min) and using polystyrene as the reference standard.

The terminal acid groups content of the polyesters of the composition according to this invention is preferably between 20 and 160 meq/kg.

The terminal acid groups content may be measured in the following way: 1.5-3 g of the polyester are placed in a 100 ml flask together with 60 ml of chloroform. After the polyester has completely dissolved 25 ml of 2-propanol are added and, immediately before the analysis, 1 ml of deionised water is also added. The solution so obtained is titrated against a previously standardised solution of NaOH in ethanol. An appropriate indicator, such as for example a glass electrode for acid-base titrations in non-aqueous solvents, is used to determine the end point of the titration. The terminal acid groups content is calculated on the basis of the NaOH solution in ethanol consumed using the following equation:

${{Terminal}\mspace{14mu}{acid}\mspace{14mu}{groups}\mspace{14mu}{content}\mspace{14mu}\left( {{meq}\text{/}{kg}\mspace{14mu}{polymer}} \right)} = \frac{\left\lfloor {\left( {V_{eq} - V_{b}} \right) \cdot T} \right\rfloor \cdot 1000}{P}$

in which: V_(eq)=ml of NaOH in ethanol solution at the end point of the titration of the sample;

-   -   V_(b)=ml of NaOH in ethanol solution required to achieve a         pH=9.5 during the blank titration;     -   T=concentration of the solution of NaOH in ethanol expressed in         moles/litre;     -   P=weight of the sample in grams.

Preferably, the polyesters of the composition according to this invention have an inherent viscosity (measured with an Ubbelohde viscometer for solutions in CHCl₃ of concentration 0.2 g/dl at 25° C.) of more than 0.3 dl/g, preferably between 0.3 and 2 dl/g, more preferably between 0.4 and 1.3 dl/g.

Preferably, the polyesters of the composition according to this invention are biodegradable. In the meaning of this invention, by biodegradable polymers are meant polymers which are biodegradable according to standard EN 13432.

The polyesters of the composition according to this invention may be synthesised by any of the processes known in the art. In particular, they may advantageously be obtained through a polycondensation reaction.

Advantageously the synthesis process may be performed in the presence of a suitable catalyst. Among such suitable catalysts mention may by way of example be made of organometallic compounds of tin, for example derivatives of stannoic acid, titanium compounds, for example orthobutyl titanate, aluminium compounds, for example Al-triisopropyl, compounds of antimony and zinc and zirconium and mixtures thereof.

In order to ensure high properties of resistance to deformation for the injection moulded articles, the composition according to this invention comprises 30-60% by weight, preferably 35-50% by weight, with respect to the sum of components i.-v., of at least one polyhydroxyalkanoate (component ii.) preferably selected from the group comprising the polyesters of lactic acid, poly-ε-caprolactone, polyhydroxybutyrate, polyhydroxybutyrate-valerate, polyhydroxybutyrate propanoate, polyhydroxybutyrate-hexanoate, polyhydroxybutyrate-decanoate, polyhydroxybutyrate-dodecanoate, polyhydroxybutyrate-esadecanoate, polyhydroxybutyrate-octadecanoate, poly 3-hydroxybutyrate-4-hydroxybutyrate. Preferably the polyhydroxyalkanoate of the composition comprises at least 80% by weight of one or more polyesters of lactic acid.

In a preferred embodiment the polyesters of lactic acid are selected from the group which comprises poly L lactic acid, poly D lactic acid, poly D-L lactic acid stereo complex, copolymers comprising more than 50% in moles of the said polyesters of lactic acid or their mixtures.

The polyesters of lactic acid containing at least 95% by weight of repetitive units deriving from L-lactic or D-lactic acid or their combinations, with a molecular weight Mw of more than 50,000 and with a shear viscosity of between 50 and 500 Pa·s, preferably between 100 and 300 Pa·s (measured according to standard ASTM D3835 at T=190° C., shear rate=1000 s⁻¹, D=1 mm, L/D=10), are particularly preferred.

In a particularly preferred embodiment of the invention, the polyester of lactic acid comprises at least 95% by weight of units deriving from L-lactic acid, ≤5% of repetitive units deriving from D-lactic acid having a melting point in the range 135-170° C., a glass transition temperature (Tg) in the range 55-65° C. and an MFR (measured according to standard ASTM-D1238 at 190° C. and 2.16 kg) in the range 1-50 g/10 min. Commercial examples of polyesters of lactic acid having these properties are for example products of the Ingeo™ trade mark Biopolymer 4043D, 3251D and 6202D.

The composition according to this invention comprises 0.01-5% by weight, preferably 0.02-3% by weight, more preferably 0.1-1% by weight, with respect to the sum of components i.-v., of at least one cross-linking agent and/or chain extender (component iii.) which improves stability to hydrolysis and is selected from compounds having di- and/or multiple functional groups incorporating isocyanate, peroxide, carbodiimide, isocyanurate, oxazoline, epoxy, anhydride or divinyl ether groups and mixtures thereof.

Preferably the cross-linking agent and/or chain extender comprises at least one compound having di- and/or multiple functional groups comprising isocyanate groups. More preferably the cross-linking agent and/or chain extender comprises at least 25% by weight of one or more compounds having di- and/or multiple functional groups incorporating isocyanate groups. Particularly preferred are mixtures of compounds having di- and/or multiple functional groups incorporating isocyanate groups with compounds having di- and/or multiple functional groups incorporating epoxy groups, even more preferably comprising at least 75% by weight of compounds having di- and/or multiple functional groups incorporating isocyanate groups.

The compounds having di- and multiple functional groups incorporating isocyanate groups are preferably selected from p-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4-diphenylmethane-diisocyanate, 1,3-phenylene-4-chloro diisocyanate, 1,5-naphthalene diisocyanate, 4,4-diphenylene diisocyanate, 3,3′-dimethyl-4,4diphenylmethane diisocyanate, 3-methyl-4,4′-diphenylmethane diisocyanate, diphenylester diisocyanate, 2,4-cyclohexane diisocyanate, 2,3-cyclohexane diisocyanate, 1-methyl 2,4-cyclohexyl diisocyanate, 1-methyl 2,6-cyclohexyl diisocyanate, bis-(isocyanate cyclohexyl) methane, 2,4,6-toluene triisocyanate, 2,4,4-diphenylether triisocyanate, polymethylene-polyphenyl-polyisocyanates, methylene diphenyl diisocyanate, triphenylmethane triisocyanate, 3,3′ditolylene-4,4-diisocyanate, 4,4′-methylenebis (2-methyl-phenyl isocyanate), hexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,2-cyclohexylene diisocyanate and their mixtures. In a preferred embodiment, the compound comprising isocyanate groups is 4,4-diphenylmethane-diisocyanate.

With regard to compounds having di- and multiple functional groups incorporating peroxide groups, these are preferably selected from benzoyl peroxide, lauroyl peroxide, isononanoyl peroxide, di-(t-butylperoxyisopropyl)benzene, t-butyl peroxide, dicumyl peroxide, alpha,alpha′-di(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5di(t-butylperoxy)hexane, t-butyl cumyl peroxide, di-t-butylperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hex-3-yne, di(4-t-butylcyclohexyl)peroxy dicarbonate, dicetyl peroxydicarbonate, dimyristyl peroxydicarbonate, 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane,di(2-ethylhexyl) peroxydicarbonate and their mixtures.

The compounds having di- and multiple functional groups incorporating carbodiimide groups which are preferably used in the composition according to this invention are selected from poly(cyclooctylene carbodiimide), poly(1,4-dimethylenecyclohexylene carbodiimide), poly(dicyclohexylmethane carbodiimide), poly(cyclohexylene carbodiimide), poly(ethylene carbodiimide), poly(butylene carbodiimide), poly(isobutylene carbodiimide), poly(nonylene carbodiimide), poly(dodecylene carbodiimide), poly(neopentylene carbodiimide), poly(1,4-dimethylene phenylene carbodiimide), poly(2,2′,6,6′-tetraisopropyldiphenylene carbodiimide) (Stabaxol® D), poly(2,4,6-triisolpropyl-1,3-phenylene carbodiimide) (Stabaxol® P-100), poly(2,6 diisopropyl-1,3-phenylene carbodiimide) (Stabaxol® P), poly(tolyl carbodiimide), poly(4,4′-diphenylmethane carbodiimide), poly(3,3′-dimethyl-4,4′-biphenylene carbodiimide), poly(p-phenylene carbodiimide), poly(m-phenylene carbodiimide), poly(3,3′-dimethyl-4,4′-diphenylmethane carbodiimide), poly(naphthylene carbodiimide), poly(isophorone carbodiimide), poly(cumene carbodiimide), p-phenylene bis(ethylcarbodiimide), 1,6-hexamethylene bis(ethylcarbodiimide), 1,8-octamethylene bis(ethylcarbodiimide), 1,10-decamethylene bis(ethylcarbodiimide), 1,12 dodecamethylene bis(ethylcarbodiimide) and their mixtures.

Examples of compounds having di- and multiple functional groups incorporating epoxy groups which may advantageously be used in the composition according to this invention are all the polyepoxides from epoxydised oils and/or styrene-glycidylether-methylmethacrylate, glycidylether methylmethacrylate, included in a range of molecular weights between 1000 and 10000 and having an epoxy number per molecule in the range from 1 to 30 and preferably between 5 and 25, and the epoxides selected from the group comprising: diethylene glycol diglycidylether, polyethylene glycol diglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, 1,2-epoxybutane, polyglycerol polyglycidyl ether, isoprene diepoxy and cycloaliphatic diepoxides, 1,4-cyclohexandimethanol diglycidyl ether, glycidyl 2-methylphenyl ether, glycerol propoxylatotriglycidyl ether, 1,4-butandiol diglycidyl ether, sorbitol polyglycidyl ether, glycerol diglycidyl ether, tetraglycidyl ether of meta-xylenediamine and the diglycidyl ether of bisphenol A and their mixtures.

Together with the compounds having di- and multiple functional groups incorporating isocyanate, peroxide, carbodiimide, isocyanurate, oxazoline, epoxy, anhydride and divinylether groups of the composition according to this invention, catalysts may be also used to increase the reactivity of the reactive groups. In the case of polyepoxides, salts of fatty acids, even more preferably calcium and zinc stearates, are preferably used.

In a particularly preferred embodiment of the invention the cross-linking agent and/or chain extender of the composition comprises compounds incorporating isocyanate groups, preferably 4,4-diphenylmethane-diisocyanate, and/or incorporating carbodiimide groups, and/or incorporating epoxy groups, preferably of the styrene-glycidylether-methylmethacrylate type.

The composition according to this invention comprises 0-10% by weight, preferably 0.1-9% by weight, more preferably 0.5-5% by weight, of at least one filler agent (component iv.) which helps to improve the dimensional stability of the injection moulded objects according to this invention and is preferably selected from kaolin, barytes, clay, talc, carbonates of calcium and magnesium, iron and lead, aluminium hydroxide, diatomaceous earth, aluminium sulfate, barium sulfate, silica, mica, titanium dioxide, wollastonite, starch, chitin, chitosane, alginates, proteins such as glutine, zein, casein, collagen, gelatine, natural rubbers, rosinic acid and their derivatives.

By the term starch are meant here all types of starch, that is: flour, native starch, hydrolysed starch, destructured starch, gelatinised starch, plasticised starch, thermoplastic starch, biofiller comprising complexed starch or mixtures thereof. Particularly suitable according to the invention are starches such as potato, maize, tapioca and pea starch.

Starches which are capable of being easily destructured and which have high initial molecular weights, such as for example potato starch and maize starch, have proved to be particularly advantageous.

The starch may be present either as such or in chemically modified form such as for example in the form of starch esters with a level of substitution of between 0.2 and 2.5, starch hydroxypropylate, or starch modified with fatty chains.

By destructured starch reference is made here to the teachings included in patents EP-0 118 240 and EP-0 327 505, this being understood to mean starch processed in such a way that it does not have the so-called “Maltese crosses” under the optical microscope in polarised light and the so-called “ghosts” under a phase contrast microscope.

Advantageously the starch is destructured by means of a process of extrusion at temperatures of between 110 and 250° C., preferably between 130° C. and 180° C., preferably at pressures between 0.1 and 7 MPa, preferably 0.3-6 MPa, preferably providing a specific energy of more than 0.1 kWh/kg during that extrusion.

Destructuring of the starch preferably takes place in the presence of 1-40% by weight with respect to the weight of the starch of one or more plasticisers selected from water and polyols having 2 to 22 carbon atoms. As far as the water is concerned, this may be water which includes that naturally present in the starch. Among the polyols, polyols having from 1 to 20 hydroxyl groups containing 2 to 6 carbon atoms, their ethers, thioethers and organic and inorganic esters are preferred. Examples of polyols are glycerine, diglycerol, polyglycerol, pentaerythritol, polyglycerol ethoxylate, ethylene glycol, polyethylene glycol, 1,2-propandiol, 1,3-propandiol, 1,4-butandiol, neopentylglycol, sorbitol monoacetate, sorbitol diacetate, sorbitol monoethoxylate, sorbitol diethoxylate, and mixtures thereof. In a preferred embodiment the starch is destructured in the presence of glycerol or a mixture of plasticisers comprising glycerol, more preferably comprising between 2 and 90% by weight of glycerol. Preferably the destructured or cross-linked starch according to this invention comprises between 1 and 40% by weight of plasticisers with respect to the weight of the starch.

When present, the starch in the composition is preferably present in the form of particles having a circular or elliptical cross-section or in any event a cross-section similar to an ellipse having an arithmetic mean diameter measured taking the major axis of the particle into consideration which is of mean diameter less than 1 micron and more preferably less than 0.5 μm.

In a preferred embodiment of this invention the filler agent comprises talc, calcium carbonate, titanium dioxide or their mixtures, present in the form of particles having a median diameter of less than 10 microns, measured taking the major axis of the particles into consideration.

In the composition according to this invention the plant fibres (component v.) are preferably selected from cellulose fibres, wood flour, hemp fibre, lignocellulose residues originating from raw materials of plant origin such as for example thistle or sunflower plants and grass cuttings.

The polymer composition according to this invention comprises 2-30% by weight of plant fibres. It has in fact been found that such a content has the effect of significantly improving the disintegratability properties of the polymer composition, making it possible at the same time to manufacture articles having a high bend temperature under load and particularly high dimensional stability, thus making it possible to prepare compositions minimising the presence of filler agents.

Moreover, the presence of plant fibres improves the mechanical properties and the heat resistance.

In a preferred embodiment, the composition according to this invention comprises from 5 to 25% by weight of plant fibres. By “dimensional stability” is meant the ability of an object to maintain its original shape over time or following annealing treatment.

It has also unexpectedly been found that the use of plant fibres having a length/diameter ratio (i.e. L/D) <40, preferably L/D<30 and even more preferably L/D<20, is particularly advantageous because in addition to contributing to the abovementioned properties of dimensional stability and high bend temperature under load they do not cause excessive increases in the elastic modulus or significant reductions in the deformation of the polymer composition at failure, nor an appreciable reduction in flowability in the fused state.

In addition to components i.-v. the composition according to this invention preferably also contains at least one other component selected from the group consisting of plasticisers, UV stabilisers, lubricants, nucleating agents, anti-caking agents, surfactants, antistatic agents, pigments, flame retardants, compatibilising agents, lignin, organic acids, antioxidants, mould prevention agents, waxes, process coadjuvants and polymer components preferably selected from the group consisting of vinyl polymers, polyesters of diacid diols which are other than polyester i., polyamides, polyurethanes, polyethers, polyureas and polycarbonates.

With regard to plasticisers, in addition to the plasticisers preferably used for the preparation of destructured starch described above, there are preferably present in the composition according to this invention one or more plasticisers selected from the group comprising phthalates, such as for example diisononyl phthalate, trimellitates, such as for example the esters of trimellitic acid with C₄-C₂₀ monoalcohols preferably selected from the group comprising n-octanol and n-decanol, and aliphatic esters having the following structure: R₁—O—C(O)—R₄—C(O)—[—O—R₂—O—C(O)—R₅—C(O)—]_(m)—O—R₃

in which:

-   R₁ is selected from one or more of the groups comprising H, linear     and branched saturated and unsaturated alkyl residues of the C₁-C₂₄     type, polyol residues esterified with C₁-C₂₄ monocarboxylic acids; -   R₂ comprises —CH₂—C(CH₃)₂—CH₂— and alkylene C₂-C₈, groups and     comprises at least 50% in moles of the said —CH₂—C(CH₃)₂—CH₂—     groups; -   R₃ is selected from one or more of the groups comprising H, linear     and branched saturated and unsaturated alkyl residues of the C₁-C₂₄     type, polyol residues esterified with C₁-C₂₄ monocarboxylic acids; -   R₄ and R₅ are the same or different, comprise one or more C₂-C₂₂,     preferably C₂-C₁₁, more preferably C₄-C₉ alkylenes and comprise at     least 50% in moles of C₇ alkylenes.

m is a number between 1 and 20, preferably 2-10, more preferably 3-7. Preferably, in the said esters at least one of the R₁ and/or R₃ groups comprises, preferably in quantities ≥10% in moles, more preferably ≥20%, even more preferably ≥25% in moles with respect to the total quantities of R₁ and/or R₃ groups, polyol residues esterified with at least one C₁-C₂₄ monocarboxylic acid selected from the group comprising stearic acid, palmitic acid, 9-ketostearic acid, 10-ketostearic acid and mixtures thereof. Examples of aliphatic esters of this type are described in Italian patent application MI2014A000030 and PCT applications PCT/EP2015/050336, PCT/EP2015/050338.

When present, the selected plasticisers are preferably present up to 10% by weight, with respect to the total weight of the composition.

The lubricants are preferably selected from esters and metal salts of fatty acids such as for example zinc stearate, calcium stearate, aluminium stearate and acetyl stearate. Preferably the composition according to this invention comprises up to 1% by weight of lubricants, more preferably up to 0.5% by weight, with respect to the total weight of the composition.

Examples of nucleating agents include the sodium salt of saccharine, calcium silicate, sodium benzoate, calcium titanate, boron nitride, isotactic polypropylene, low molecular weight PLA. These additives are preferably added in quantities up to 10% by weight and more preferably between 2 and 6% by weight with respect to the total weight of the composition.

Pigments may also be added if necessary, for example titanium dioxide, clays, copper phthalocyanin, titanium dioxide, silicates, oxides and hydroxides of iron, carbon black and magnesium oxide. These additives will preferably be added up to 10% by weight.

Among the vinyl polymers, those preferred are: polyethylene, polypropylene, their copolymers, polyvinyl alcohol, polyvinyl acetate, polyethyl vinyl acetate and polyethylene vinyl alcohol, polystyrene, chlorinated vinyl polymers, polyacrylates.

Among the chlorinated vinyl polymers these are here intended to include in addition to polyvinyl chloride: polyvinylidene chloride, polyethylene chloride, poly(vinyl chloride-vinyl acetate), poly(vinyl chloride-ethylene), poly(vinyl chloride-propylene), poly(vinyl chloride-styrene), poly(vinyl chloride-isobutylene) and copolymers in which polyvinyl chloride represents more than 50% in moles. The said copolymers may be random, block or alternating.

With regard to the polyamides of the composition according to this invention, these are preferably selected from the group consisting of polyamide 6 and 6,6, polyamide 9 and 9,9, polyamide 10 and 10,10, polyamide 11 and 11,11, polyamide 12 and 12,12 and their combinations of the 6/9, 6/10, 6/11, 6/12 type, their mixtures and both random and block copolymers.

Preferably the polycarbonates of the composition according to this invention are selected from the group comprising polyalkylene carbonates, more preferably polyethylene carbonates, polypropylene carbonates, polybutylene carbonates, their mixtures and copolymers both random and block copolymers.

Among the polyethers, those preferred are those selected from the group consisting of polyethylene glycols, polypropylene glycols, polybutylene glycols their copolymers and their mixtures with molecular weights from 70,000 to 500,000.

With regard to polyesters of diacid diols which are other than polyester i., these preferably comprise:

-   -   a) a dicarboxylic component comprising, with respect to the         total dicarboxylic component,         -   a1) 20-100% in moles of units deriving from at least one             aromatic dicarboxylic acid,         -   a2) 0-80% in moles of units deriving from at least one             saturated aliphatic dicarboxylic acid,         -   a3) 0-5% in moles of units deriving from at least one             unsaturated aliphatic dicarboxylic acid;     -   b) a diol component comprising, with respect to the total diol         component,         -   b1) 95-100% in moles of units deriving from at least one             saturated aliphatic diol;         -   b2) 0-5% in moles of units deriving from at least one             unsaturated aliphatic diol.

Preferably the aromatic dicarboxylic acids, saturated aliphatic dicarboxylic acids, unsaturated aliphatic dicarboxylic acids, saturated aliphatic diols and unsaturated aliphatic diols for the said polyesters are selected from those described above for the polyester (component i.) of the composition according to this invention. More preferably the said diacid-diol polyesters which are other than polyester i. are selected from the group consisting of poly(ethylene terephthalate), poly(propylene terephthalate), poly(butylene terephthalate), poly(ethylene 2,5furandicarboxylate), poly(propylene 2,5-furandicarboxylate), poly(butylene 2,5-furandicarboxylate) and block or random copolymers of the poly(alkylene 2,5-furandicarboxylate-co-alkylene terephthalate) type.

The production of the polymer composition according to this invention can be carried out by any of the processes known in the art. Advantageously, the polymer composition according to this invention is produced by means of extrusion processes in which the polymer components are mixed in the fused state. In extruding the composition the components may be fed all together or one or more of them may be fed separately along the extruder.

This invention also relates to injection moulded articles, comprising the said polymer composition, which in fact has processability and performance in use properties which render it particularly suitable for this use. Its properties in fact make it possible to manufacture injection moulded articles having good resistance to deformation, high dimensional stability and bend temperature under load properties which are able to disintegrate and biodegrade in industrial composting processes. Preferably, injection moulded articles, comprising the composition according to this invention, are biodegradable according to EN 13432.

For example, the polymer composition according to the invention is particularly suitable for the manufacture injection moulded articles such as for example disposable cutlery, plates and cups, rigid containers, capsules for the dispensing of beverages, preferably hot beverages, lids and covers, and food packaging which can be heated in conventional and microwave ovens. Preferably, the injection moulded articles are characterised by G′ modulus values, obtained at 70° C. through dynamic mechanical-torsional analysis (DMTA), higher than 60 MPa, preferably higher than 70 MPa, more preferably higher than 80 MPa.

The composition according to this invention and the injection moulded articles it comprises are preferably characterised by a THF content of below 10 mg/kg, preferably <5 mg/kg, and are capable of being used in contact with food, as occurs for example in the case of capsules for the dispensing of beverages. In a preferred embodiment this invention relates to a capsule for the dispensing of beverages characterised by a THF content of below 3 mg/kg, preferably 1 mg/kg. In the case of the compositions which comprise polyesters comprising 1,4-butylene dicarboxylate units as component i. the said low THF content can be obtained by subjecting the compositions according to this invention, or the injection moulded articles comprising them, to at least one stage of volatilisation of the THF.

The polymer composition according to this invention has the further advantage of being able to be fed to conventional machines without requiring substantial changes in normal operating conditions, in comparison with other conventional polymers such as for example polyethylene, polypropylene, polystyrene and ABS. Preferably, in the case of objects having a maximum thickness of the order of 1 millimetre, these may be moulded using a melt temperature of 210° C., an oleodynamic pressure of 80 bar, a cooling time of 4 sec and a cycle time of 12 sec.

The injection moulded articles comprising the composition according to this invention may also undergo hot annealing treatment at temperatures of between 60 and 120° C. This invention also relates to articles obtained by means of the said annealing treatment (“annealed products”).

The said annealing treatments may advantageously be carried out in an unconfined environment at constant temperature, for example within a stove. In this case the annealing treatments are preferably carried out at temperatures of between 80 and 120° C. with residence times of 30 sec-60 min, preferably 40 sec-30 min and even more preferably 40 sec-5 min, with this being particularly advantageous from the production point of view. The specific conditions used will vary according to the dimensions of the object which is subjected to annealing treatment and the level of heat resistance required by the application. In general, in the case of objects of great thickness it is preferable to use higher temperatures or longer residence times.

The said annealing treatments may also be carried out in a confined environment, for example within preheated moulds at constant temperature, preferably between 80 and 100° C., for 1-5 minutes. The specific conditions used will vary according to the dimensions of the object which is subjected to annealing treatment. In general, in the case of great thickness it is preferable to use longer residence times.

The invention will now be illustrated through a number embodiments which are intended to be by way of example and do not limit the scope of protection of this patent application.

EXAMPLES

Component i

-   i=Poly(1,4-butylene succinate) (“PBS”) prepared according to the     following method: 17150 g of succinic acid, 14000 g of     1,4-butandiol, 26.75 g of glycerine and 2.0 g of an 80% by weight     ethanolic solution of diisopropyl triethanolamine titanate (Tyzor     TE, containing 8.2% by weight of titanium) were added to a steel     reactor having a geometrical capacity of 40 litres fitted with a     mechanical stirring system, an inlet for nitrogen, a distillation     column, a knock-down system for high boiling point components and a     connection to a high vacuum system in a diol/dicarboxylic acid (MGR)     molar ratio of 1.08. The temperature of the mass was gradually     raised to 230° C. over a period of 120 minutes. When 95% of the     theoretical water has been distilled off, 21.25 g of tetra n-butyl     titanate (corresponding to 119 ppm of metal with respect to the     quantities of poly1,4-butylene succinate that would be theorically     obtainable by converting all the succinic acid fed to the reactor)     were added. The temperature of the reactor was then raised to     235-240° C. and the pressure was gradually reduced to a value below     2 mbar over a period of 60 minutes. The reaction was allowed to     proceed for the time required to obtain a poly(1,4-1,4-butylene     succinate) with an MFR of approximately 7 (g/10 minutes at 190° C.     and 2.16 kg), and the material was then discharged in the form of a     filament into a water bath and granulated.

Component ii

-   ii=Ingeo 3251D polylactic acid (“PLA”), MFR 28.7/10 min (at 190° C.,     2.16 kg).

Component iii

-   iii=masterbatch comprising 10% by weight of Joncryl ADR4368CS     (styrene-glycidylether-methylmethacrylate copolymer) and 90% by     weight of component ii.

Component iv

-   iv-1=micronised talc having a median diameter of 1.9 microns (ISO     13317-3), Mistron R10C commercial grade from Imerys. -   iv-2=CaCO₃ Calcitec M/ALFA from Mineraria Sacilese s.p.a.

Component v

-   v=fibrillar cellulose fibre having a mean fibre length of 550     microns L/D=18 Alpha-Cel C10 commercial grade from International     Fiber Europe NV.

Examples 1-2—Production of Injection Moulded Articles Comprising the Composition According to this Invention; Examples 3-6 (Comparative)

TABLE 1 Compositions in Examples 1-6 Components (% wt) Example i ii iii iv-1 iv-2 v 1 44.5 42 2 1.5 — 10 2 32.1 44.3 2 1.5 — 20.1 3 (comparative) 32.1 44.3 2 1.5 20.1 — 4 (comparative) 32.1 44.3 2 21.6 — — 5 (comparative) 44.5 42 2 1.5 10 — 6 (comparative) 44.5 42 2 11.5 — —

The compositions in Table 1 were fed respectively to an Icma San Giorgio MCM 25 HT model co-rotating twin screw extruder under the following operating conditions:

Screw diameter (D)=25 mm;

L/D=52;

Rotation speed=150 rpm (Example 1), 180 rpm (Example 2);

Temperature profile=50-150-200×9-155×3° C.;

Throughput 10.1 kg/h (Example 1), 7.1 kg/h (Example 2).

The granules so obtained were then injection moulded on a Sandretto S7/60 model press in a mould for the production of capsules for the dispensing of beverages (external flange diameter 35.5 mm, external diameter of the capsule base 30.3 mm, side wall thickness 0.65 mm, height 22.2 mm), using the following operating conditions for injection moulding:

Injection T° C.=230° C. (Example 1), 200° C. (Example 2);

Injection pressure=90 bar;

Injection time=1.5 sec (Example 1), 2 sec (Example 2);

Cooling time=2.7 sec (Example 1), 2.5 sec (Example 2);

Cycle time=7.9 sec (Example 1), 7.5 sec (Example 2);

Screw rotation speed=180 rpm (Example 1), 200 rpm (Example 2);

Comparative examples 3 and 4 were obtained under the operational conditions employed in example 2, while comparative examples 5 and 6 were obtained under the operational conditions employed in example 1.

Slabs (length 80 mm, width 70 mm, thickness 1 mm) were also injection moulded under the same operating conditions as mentioned above and from these were obtained bars (length 30 mm, width 6 mm, thickness 1 mm) which then underwent dynamic mechanical-torsional analysis (DMTA) in torsional mode using an Ares G2 rotational rheometer from TA Instrument. The samples were heated from 25° C. to 130° C. at 3° C./min imposing a deformation of 0.1% and a frequency of 1 Hz. The compositions moulded in this way were characterised at 70° C. (conditions representative of the dispensing of hot coffee) by sufficiently high G′ values (shown in the Table 2 below) to permit them to be used for the production of capsules for the dispensing of beverages having high dimensional stability under the conditions of the dispensing of hot beverages.

TABLE 2 DMTA characterization Example G′ @ 70° C. (MPa) 1 90 2 83 3 (comparative) 42 4 (comparative) 51 5 (comparative) 52 6 (comparative) 56

From the G′ values indicated in Table 2, the compositions of Examples 1 and 2 containing plant fibres show a higher resistance to deformation at 70° C. when compared to compositions comprising CaCO₃ or talc (comparative Examples 3-6). 

The invention claimed is:
 1. A polymer composition for the production of injection moulded articles comprising, with respect to the sum of components i.-v.: i) 20-60% by weight of at least one polyester i. comprising: a) a dicarboxylic component comprising with respect to the total dicarboxylic component: a1) 0-20% in moles of units deriving from at least one aromatic dicarboxylic acid, a2) 80-100% in moles of units deriving from at least one saturated aliphatic dicarboxylic acid, a3) 0-5% in moles of units deriving from at least one unsaturated aliphatic dicarboxylic acid; b) a diol component comprising, with respect to the total diol component: b1) 95-100% in moles of units deriving from at least one saturated aliphatic diol; b2) 0-5% in moles of units deriving from at least one unsaturated aliphatic diol; ii) 30-60% by weight of at least one polyhydroxyalkanoate ii.; iii) 0.01-5% by weight of at least one cross-linking agent and/or a chain extender iii. comprising at least one compound having di- and/or multiple functional groups comprising isocyanate, peroxide, carbodiimide, isocyanurate, oxazoline, epoxy, anhydride, divinyl ether groups and mixtures thereof; iv) 0-10% by weight of at least one filler agent; v) 2-30% by weight of plant fibres.
 2. The polymer composition according to claim 1, in which the said at least one polyester i. comprises an aliphatic polyester (AP), comprising a dicarboxylic component consisting of, with respect to the total moles of the dicarboxylic component, 95-100% in moles of units deriving from at least one saturated aliphatic dicarboxylic acid and 0-5% in moles of units deriving from at least one unsaturated aliphatic dicarboxylic acid, and a diol component comprising, with respect to the total moles of the diol component, 95-100% in moles of units deriving from at least one saturated aliphatic diol and 0-5% in moles of units deriving from at least one unsaturated aliphatic diol.
 3. The polymer composition according to claim 2, in which the said aliphatic polyester (AP) is selected from the group consisting of poly(1,4-butylene succinate), poly(1,4-butylene adipate), poly (1,4-butylene azelate), poly(1,4-butylene sebacate), poly(1,4-butylene adipate-co-1,4-butylene succinate), poly(1,4-butylene azelate-co-1,4-butylene succinate), poly(1,4-butylene sebacate-co-1,4-butylene succinate), and poly(1,4-butylene succinate-co-1,4-butylene adipate-co-1,4-butylene azelate).
 4. The polymer composition according to claim 2, wherein the said aliphatic polyester (AP) is poly(1,4-butylene succinate).
 5. The polymer composition according to claim 1, in which the said at least one polyhydroxyalkanoate ii. is selected from the group consisting of polyesters of lactic acid, poly-ε-caprolactone, polyhydroxybutyrate, polyhydroxybutyrate-valerate, polyhydroxybutyrate propanoate, polyhydroxybutyrate-hexanoate, polyhydroxybutyrate-decanoate, polyhydroxybutyrate-dodecanoate, polyhydroxybutyrate-esadecanoate, polyhydroxybutyrate-ottadecanoate, and poly-3-hydroxybutyrate 4-hydroxybutyrate.
 6. An injection moulded article comprising the polymer composition according to claim
 1. 7. The injection moulded article according to claim 6, selected from the group consisting of disposable cutlery, plates, cups, rigid containers, capsules for the dispensing of beverages, lids, covers, or containers for food which can be heated in conventional or microwave ovens.
 8. A capsule-for the dispensing of beverages comprising the composition according to claim 1, having a THF content below 3 mg/kg.
 9. The polymer composition according to claim 2, in which the said at least one polyhydroxyalkanoate ii. is selected from the group consisting of polyesters of lactic acid, poly-ε-caprolactone, polyhydroxybutyrate, polyhydroxybutyrate-valerate, polyhydroxybutyrate propanoate, polyhydroxybutyrate-hexanoate, polyhydroxybutyrate-decanoate, polyhydroxybutyrate-dodecanoate, polyhydroxybutyrate-esadecanoate, polyhydroxybutyrate-ottadecanoate, and poly-3-hydroxybutyrate 4-hydroxybutyrate.
 10. The polymer composition according to claim 3, in which the said at least one polyhydroxyalkanoate ii. is selected from the group consisting of polyesters of lactic acid, poly-ε-caprolactone, polyhydroxybutyrate, polyhydroxybutyrate-valerate, polyhydroxybutyrate propanoate, polyhydroxybutyrate-hexanoate, polyhydroxybutyrate-decanoate, polyhydroxybutyrate-dodecanoate, polyhydroxybutyrate-esadecanoate, polyhydroxybutyrate-ottadecanoate, and poly-3-hydroxybutyrate 4-hydroxybutyrate.
 11. The polymer composition according to claim 4, in which the said at least one polyhydroxyalkanoate ii. is selected from the group consisting of polyesters of lactic acid, poly-ε-caprolactone, polyhydroxybutyrate, polyhydroxybutyrate-valerate, polyhydroxybutyrate propanoate, polyhydroxybutyrate-hexanoate, polyhydroxybutyrate-decanoate, polyhydroxybutyrate-dodecanoate, polyhydroxybutyrate-esadecanoate, polyhydroxybutyrate-ottadecanoate, and poly-3-hydroxybutyrate 4-hydroxybutyrate.
 12. An injection moulded article comprising the polymer composition according to claim
 2. 13. An injection moulded article comprising the polymer composition according to claim
 3. 14. An injection moulded article comprising the polymer composition according to claim
 4. 15. An injection moulded article comprising the polymer composition according to claim
 5. 16. A capsule for the dispensing of beverages comprising the composition according to claim 2, having a THF content below 3 mg/kg.
 17. A capsule for the dispensing of beverages comprising the composition according to claim 3, having a THF content below 3 mg/kg.
 18. A capsule for the dispensing of beverages comprising the composition according to claim 4, having a THF content below 3 mg/kg.
 19. A capsule for the dispensing of beverages comprising the composition according to claim 5, having a THF content below 3 mg/kg.
 20. An injection moulded article comprising the polymer composition according to claim
 9. 21. The polymer composition according to claim 1, wherein the plant fibres are selected from cellulose fibres, wood flour, hemp fibre, lignocellulose residues originating from raw materials of plant origin.
 22. The polymer composition according to claim 1, which comprises 0.1-9% by weight of at least one filler agent having a median diameter of less than 10 microns and being selected from talc, calcium carbonate, titanium dioxide and mixtures thereof. 